30分钟小Demo，基于Socket套接字实现即时通信IM

if (userBean.getNumber() == entry.getValue().getNumber() && !entry.getValue().isMatching() && !userBean.getId().equals(entry.getValue().getId())) {

//匹配成功

//对方信息

UserBean value = entry.getValue();

//将双方匹配状态都改为true

changeStatus(userBean.getId());

changeStatus(value.getId());

UserMessageBean userMessageBean1 = new UserMessageBean(value.getId(), value.getNumber(), value.getName(), value.getFace());

UserMessageBean userMessageBean2 = new UserMessageBean(userBean.getId(), userBean.getNumber(), userBean.getName(), userBean.getFace());

//汇报双方id

PrintStream printStream1 = new PrintStream(socket.getOutputStream());

printStream1.println(new Gson().toJson(userMessageBean1));

PrintStream printStream2 = new PrintStream(value.getSocket().getOutputStream());

printStream2.println(new Gson().toJson(userMessageBean2));

//匹配成功

System.out.println(“匹配成功”);

break;

}

}

System.out.println(“为用户创建消息收发流”);

//为用户创建消息收发流

new Thread(new ServerThread(socket)).start();

}

} catch (

IOException e) {

e.printStackTrace();

System.out.println(“服务异常”);

}

}

private void changeStatus(String id) {

UserBean userBean = sockets.get(id);

userBean.setMatching(true);

sockets.put(id, userBean);

}

private String getMd5(String text) {

char[] hexDigits = {

‘0’, ‘1’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’, ‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’

};

try {

byte[] btInput = text.getBytes();

// 获得MD5摘要算法的 MessageDigest 对象

MessageDigest mdInst = MessageDigest.getInstance(“MD5”);

// 使用指定的字节更新摘要

mdInst.update(btInput);

// 获得密文

byte[] md = mdInst.digest();

// 把密文转换成十六进制的字符串形式

int j = md.length;

char[] str = new char[j * 2];

int k = 0;

for (byte byte0 : md) {

str[k++] = hexDigits[byte0 >>> 4 & 0xf];

str[k++] = hexDigits[byte0 & 0xf];

}

return new String(str);

} catch (Exception e) {

return null;

}

}

private int flag = 100;

private String getUserId() {

flag++;

if (flag == 999) {

flag = 100;

}

String randomStr = ((int) (Math.random() * 999999)) + “”;

return getMd5(System.currentTimeMillis() + randomStr) + flag;

}

}

---

ServerThread类：每一个用户都有着自己的线程，当收到这个消息，就会转发到对应用户的Socket，达成消息转发！

public class ServerThread implements Runnable {

private BufferedReader bufferedReader;

private Socket socket;

public ServerThread(Socket socket) {

this.socket = socket;

try {

bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

} catch (IOException e) {

e.printStackTrace();

}

}

private String userId = null;

@Override

public void run() {

userId = getUserId();

String content;

while (null != (content = readFromClient())) {

System.out.println(“对方发来消息:” + content);

//向指定用户发送消息

try {

ContentBean contentBean = new Gson().fromJson(content, ContentBean.class);

UserBean userBean = Server.sockets.get(contentBean.getToId());

Socket socket = userBean.getSocket();

MessageBean messageBean = new MessageBean(2, contentBean.getFaceId(), contentBean.getName(), contentBean.getContent());

PrintStream printStream = new PrintStream(socket.getOutputStream());

printStream.println(new Gson().toJson(messageBean));

System.out.println(“转发成功”);

} catch (Exception e) {

e.printStackTrace();

}

}

}

private String readFromClient() {

try {

String s = bufferedReader.readLine();

return s;

} catch (Throwable e) {

e.printStackTrace();

Server.sockets.remove(userId);

}

return null;

}

private String getMd5(String text) {

char[] hexDigits = {

‘0’, ‘1’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’, ‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’

};

try {

byte[] btInput = text.getBytes();

// 获得MD5摘要算法的 MessageDigest 对象

MessageDigest mdInst = MessageDigest.getInstance(“MD5”);

// 使用指定的字节更新摘要

mdInst.update(btInput);

// 获得密文

byte[] md = mdInst.digest();

// 把密文转换成十六进制的字符串形式

int j = md.length;

char[] str = new char[j * 2];

int k = 0;

for (byte byte0 : md) {

str[k++] = hexDigits[byte0 >>> 4 & 0xf];

str[k++] = hexDigits[byte0 & 0xf];

}

return new String(str);

} catch (Exception e) {

return null;

}

}

private int flag = 100;

private String getUserId() {

flag++;

if (flag == 999) {

flag = 100;

}

String randomStr = ((int) (Math.random() * 999999)) + “”;

return getMd5(System.currentTimeMillis() + randomStr) + flag;

}

class ContentBean {

/**

• content : 就到家

• toId : af5484ade61722c4f54855bc0d188b6f102

*/

private String content;

private String name;

private int faceId;

private String toId;

public String getContent() {

return content;

}

public void setContent(String content) {

this.content = content;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getFaceId() {

return faceId;

}

public void setFaceId(int faceId) {

this.faceId = faceId;

}

public String getToId() {

return toId;

}

public void setToId(String toId) {

this.toId = toId;

}

}

}

最后还剩下三个Bean类，分别是：消息转发的内容、用户的基本信息、用户信息交互类

消息转发的内容（MessageBean）

/**

• 消息转发体

*/

public class MessageBean {

private int type;

private int face;

private String name;

private String message;

public MessageBean(int type, int face, String name, String message) {

this.type = type;

this.face = face;

this.name = name;

this.message = message;

}

public int getType() {

return type;

}

public void setType(int type) {

this.type = type;

}

public int getFace() {

return face;

}

public void setFace(int face) {

this.face = face;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getMessage() {

return message;

}

public void setMessage(String message) {

this.message = message;

}

}

---

用户的基本信息（UserBean）

public class UserBean {

private String id;

private Socket socket;

private int number;

private String name;

private int face;

private boolean isMatching;

public UserBean(String id, Socket

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socket, int number, String name, int face) {

this.id = id;

this.socket = socket;

this.number = number;

this.name = name;

this.face = face;

}

public String getId() {

return id;

}

public void setId(String id) {

this.id = id;

}

public Socket getSocket() {

return socket;

}

public void setSocket(Socket socket) {

this.socket = socket;

}

public int getNumber() {

return number;

}

public void setNumber(int number) {

this.number = number;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getFace() {

return face;

}

public void setFace(int face) {

this.face = face;

}

public boolean isMatching() {

return isMatching;

}

public void setMatching(boolean matching) {

isMatching = matching;

}

@Override

public String toString() {

return “UserBean{” +

“id='” + id + ‘’’ +

“, socket=” + socket +

“, number=” + number +

“, name='” + name + ‘’’ +

“, face=” + face +

‘}’;

}

}

---

用户信息交互类（UserMessageBean）

public class UserMessageBean {

private String userId;

private int number;

private String name;

private int face;

public UserMessageBean(String userId, int number, String name, int face) {

this.userId = userId;

this.number = number;

this.name = name;

this.face = face;

}

public String getUserId() {

return userId;

}

public void setUserId(String userId) {

this.userId = userId;

}

public int getNumber() {

return number;

}

public void setNumber(int number) {

this.number = number;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getFace() {

return face;

}

public void setFace(int face) {

this.face = face;

}

}

结构就是这样的(我可能要加东西，所以就用了SpringBoot)：

---

客户端（移动端）

因为这一切涉及到耗时操作，所以均在子线程中完成，然后与主线程通讯完成更新UI操作，列出主要代码，完整版已提交Github

public class Client {

private int number;

private int face;

private String name;

private Context context;

public static Socket socket = null;

最后

我还通过一些渠道整理了一些大厂真实面试主要有：蚂蚁金服、拼多多、阿里云、百度、唯品会、携程、丰巢科技、乐信、软通动力、OPPO、银盛支付、中国平安等初，中级，高级Java面试题集合，附带超详细答案，希望能帮助到大家。

还有专门针对JVM、SPringBoot、SpringCloud、数据库、Linux、缓存、消息中间件、源码等相关面试题。

ce() {

return face;

}

public void setFace(int face) {

this.face = face;

}

}

结构就是这样的(我可能要加东西，所以就用了SpringBoot)：

---

客户端（移动端）

因为这一切涉及到耗时操作，所以均在子线程中完成，然后与主线程通讯完成更新UI操作，列出主要代码，完整版已提交Github

public class Client {

private int number;

private int face;

private String name;

private Context context;

public static Socket socket = null;

最后

我还通过一些渠道整理了一些大厂真实面试主要有：蚂蚁金服、拼多多、阿里云、百度、唯品会、携程、丰巢科技、乐信、软通动力、OPPO、银盛支付、中国平安等初，中级，高级Java面试题集合，附带超详细答案，希望能帮助到大家。

[外链图片转存中…(img-pzb7cw9V-1716398434916)]

还有专门针对JVM、SPringBoot、SpringCloud、数据库、Linux、缓存、消息中间件、源码等相关面试题。

[外链图片转存中…(img-8mXlCacT-1716398434916)]